page_title: Paul Scherrer Institute
section_title: History
hierarchical_section_title: Paul Scherrer Institute / History
caption_attribution_description: Deutsch: Paul Scherrer Institut, Areal Ost, Würenlingen
context_page_description: The Paul Scherrer Institute is a multi-disciplinary research institute for natural and engineering sciences in Switzerland. It is located in the Canton of Aargau in the municipalities Villigen and Würenlingen on either side of the River Aare, and covers an area over 35 hectares in size. Like ETH Zurich and EPFL, PSI belongs to the Swiss Federal Institutes of Technology Domain of the Swiss Confederation. The PSI employs around 2100 people. It conducts basic and applied research in the fields of matter and materials, human health, and energy and the environment. About 37 % of PSI’s research activities focus on material sciences, 24 % on life sciences, 19 % on general energy, 11 % on nuclear energy and safety, and 9 % on particle physics.
  PSI develops, builds and operates large and complex research facilities and makes them available to the national and international scientific communities. In 2017, for example, more than 2500 researchers from 60 different countries came to PSI to take advantage of the concentration of large-scale research facilities in the same location, which is unique worldwide.
context_section_description: The institute, named after the Swiss physicist Paul Scherrer, was created in 1988 when EIR (Eidgenössisches Institut für Reaktorforschung, Swiss Federal Institute for Reactor Research, founded in 1960) was merged with SIN (Schweizerisches Institut für Nuklearphysik, Swiss Institute for Nuclear Research, founded in 1968). The two institutes on opposite sides of the River Aare served as national centres for research: one focusing on nuclear energy and the other on nuclear and particle physics. Over the years, research at the centres expanded into other areas, and nuclear and reactor physics accounts for just 11 percent of the research work at PSI today. Since Switzerland decided in 2011 to phase out nuclear energy, this research has primarily been concerned with questions of safety, such as how to store radioactive waste safely in a deep geological repository.
  Since 1984, PSI has operated (initially as SIN) the Centre for Proton Therapy for treating patients with eye melanomas and other tumours located deep inside the body. More than 9000 patients have been treated there until now (status 2020). 
  The institute is also active in space research. For example, in 1990 PSI engineers built the detector of the EUVITA telescope for the Russian satellite Spectrum X-G, and later also supplied NASA and ESA with detectors to analyse radiation in space. In 1992, physicists used accelerator mass spectrometry and radiocarbon methods to determine the age of Ötzi, the mummy found in a glacier in the Ötztal Alps a year earlier, from small samples of just a few milligrams of bone, tissue and grass. They were analysed at the TANDEM accelerator on the Hönggerberg near Zurich, which at the time was jointly operated by ETH Zurich and PSI.
  In 2009, the Indian-born British structural biologist Venkatraman Ramakrishnan was awarded the Nobel Prize in Chemistry for, among other things, his research at the Synchrotron Light Source Switzerland (SLS). The SLS is one of PSI's four large-scale research facilities. His investigations there enabled Ramakrishnan to clarify what ribosomes look like and how they function at the level of individual molecules. Using the information encoded in the genes, ribosomes produce proteins that control many chemical processes in living organisms. 
  In 2010, an international team of researchers at PSI used negative muons to perform a new measurement of the proton and found that its radius is significantly smaller than previously thought: 0.84184 femtometers instead of 0.8768. According to press reports, this result was not only surprising, it could also call previous models in physics into question. The measurements were only possible with PSI's 590 MeV proton accelerator HIPA because its secondarily generated muon beam is the only one worldwide that is intense enough to conduct the experiment.
  In 2011, researchers from PSI and elsewhere succeeded in deciphering the basic structure of the protein molecule rhodopsin with the help of the SLS. This optical pigment acts as a kind of light sensor and plays a decisive role in the process of sight.  
  A so-called ‘barrel pixel detector’ built at PSI was a central element in the CMS detector at the Geneva nuclear research centre CERN, and was thus involved in detecting the Higgs boson. This discovery, announced on 4 July 2012, was awarded the Nobel Prize in Physics one year later.
  In January 2016, 20 kilograms of plutonium were taken from PSI to the USA. According to a newspaper report, the federal government had a secret plutonium storage facility in which the material had been kept since the 1960s to construct an atomic bomb as planned at the time. The Federal Council denied this, maintaining the plutonium-239 content of the material was below 92 percent, which meant it was not weapons-grade material. The idea was rather to use the material obtained from reprocessed fuel rods of the Diorit research reactor, which was operated from 1960 to 1977, to develop a new generation of fuel element types for nuclear power plants. This, however, never happened. By the time it was decided, in 
caption: PSI administration building in PSI East in Würenlingen
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